This category coordinates physical resources — GPUs, storage, bandwidth, sensors — through a token instead of a contract with a provider. The idea is old; what changed is that AI training made the resource scarce enough for the coordination to be worth something.
The useful question for each one is whether anybody is paying for the resource in the currency the network sells, or whether demand is denominated in token emissions. Networks in the first group have revenue; networks in the second have a subsidy.
DePIN — decentralised physical infrastructure — is the wider label for the same pattern applied to wireless coverage, mapping and energy. The economics are identical: emissions bootstrap supply, and the test is what happens when they taper.